Power Stations Operations

This work proposes a paradigm shift in nuclear safety. Fission and fusion phenomena are treated as inertial processes referring to the instant of fission 1n0 capture or union of nuclei. This simple supposition has profound implications when applied to the thermodynamic understanding of a nuclear engine. MeV release from a mass defect is: independent of terrestrial reference; not affected by temperature, kinetic, or physical potential; a single phenomenon describes the macro; and has no enthalpic meaning. The only appropriate descriptive vehicle for nuclear phenomena lies with Second Law exergy analysis, treating its MeV release as a thermodynamic potential. Such potential is termed an ultimate “Free Exergy,” consisting of both recoverable and irreversible portions. In transference to a coolant the recoverable release produces an exergetic increase (ṁΔg), the fluid exergy’s T_{Ref} being explicitly computed from an Inertial Conversion Factor (Ξ). Importantly, Ξ also transforms recoverable nuclear release to an explicit, and consistent, thermal power (ṁΔh). This approach demands reinterpretation of Einstein’s ΔE = c^2Δm by describing his ΔE, not as an ΔEnergy, but an ultimate ΔFree Exergy.
Asserted is that nuclear phenomena traditionally have had no direct computational nexus with thermodynamics. Since N Reactor days, there has been no direct nexus between nuclear power and its resultant energy flow. N Reactor’s neutron flux was not well measured, but was the motive force behind delivering 4000 MWt to the Columbia River. It is well known that neutron flux in a 1270 MWe PWR is approximately 1.0x10^13 1^n cm-2sec-1. A back-calculated flux based on a thermal rating of 3640 MWt produces twice this flux. From the time of the Manhattan Project, nuclear engineers have treated flux as a relative parameter: hard to measure, a relative value to be normalized, is not uniform in the axial or radial, etc.

This work proposes a paradigm shift in nuclear safety. Fission and fusion phenomena are treated as inertial processes referring to the instant of fission 1n0 capture or union of nuclei. This simple supposition has profound implications when applied to the thermodynamic understanding of a nuclear engine. MeV release from a mass defect is: independent of terrestrial reference; not affected by temperature, kinetic, or physical potential; a single phenomenon describes the macro; and has no enthalpic meaning. The only appropriate descriptive vehicle for nuclear phenomena lies with Second Law exergy analysis, treating its MeV release as a thermodynamic potential. Such potential is termed an ultimate “Free Exergy,” consisting of both recoverable and irreversible portions. In transference to a coolant the recoverable release produces an exergetic increase (ṁΔg), the fluid exergy’s T_{Ref} being explicitly computed from an Inertial Conversion Factor (Ξ). Importantly, Ξ also transforms recoverable nuclear release to an explicit, and consistent, thermal power (ṁΔh). This approach demands reinterpretation of Einstein’s ΔE = c2Δm by describing his ΔE, not as an ΔEnergy, but an ultimate ΔFree Exergy.
Asserted is that nuclear phenomena traditionally have had no direct computational nexus with thermodynamics. Since N Reactor days, there has been no direct nexus between nuclear power and its resultant energy flow. N Reactor’s neutron flux was not well measured, but was the motive force behind delivering 4000 MWt to the Columbia River. It is well known that neutron flux in a 1270 MWe PWR is approximately 1.0x1013 1n0 cm-2sec-1. A back-calculated flux based on a thermal rating of 3640 MWt produces twice this flux. From the time of the Manhattan Project, nuclear engineers have treated flux as a relative parameter: hard to measure, a relative value to be normalized, is not uniform in the axial or radial, etc.

The cumulative global capacity of organic Rankine cycle (ORC) power systems for the conversion of renewable and waste thermal energy is undergoing a rapid growth and is estimated to be approx. 2000 MWe considering only installations that went into operation after 1995. The potential for the conversion of the thermal power coming from liquid-dominated geothermal reservoirs, waste heat from primary engines or industrial processes, biomass combustion, and concentrated solar radiation into electricity is arguably enormous. ORC technology is possibly the most flexible in terms of capacity and temperature level and is currently often the only applicable technology for the conversion of external thermal energy sources. In addition, ORC power systems are suitable for the cogeneration of heating and/or cooling, another advantage in the framework of distributed power generation. Related research and development is therefore very lively. These considerations motivated the effort documented in ...

This paper presents an on-line meth od which detects steam generator tube leaks and the heat exchanger in which the leak occurs. This method (the Tu be Failure Model) has been demonstrated by direct testing exp erience. It is based on the Input/Loss Method, a patented method (1994-2004) which computes fuel chemistry, h eating value and fuel flow by integratin g efflu en t measurements (CEMS data) with thermodynamics. This paper explains the technology supporting the detection of tube failures, the method of identifying the location of the failure, and cites direct experience of detecting tube failures at two power plants. Most importantly, this paper presents the results of direct testing at the Boardman Coal Plant in which high energy steam/water lines were routed from the drain headers of all major heat exchangers into the combustion space. When allo wed flow, these lines were used to emulate tube leaks from any of the major heat exchangers. Their flow rates and locations were then compared to Tube Failure Model predications. This testing is considered significant as for the first time Äheat rate effects of tube failures will be directly determined; and, further, this testing will provide the Tube Failure Model its on-line proof-of-process.

This paper presents an on-line meth od which detects steam generator tube leaks and the heat exchanger in which the leak occurs. This method (the Tu be Failure Model) has been demonstrated by direct testing exp erience. It is based on the Input/Loss Method, a patented method (1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004) which computes fuel chemistry, h eating value and fuel flow by integratin g efflu en t measurements (CEMS data) with thermodynamics. This paper explains the technology supporting the detection of tube failures, the method of identifying the location of the failure, and cites direct experience of detecting tube failures at two power plants. Most importantly, this paper presents the results of direct testing at the Boardman Coal Plant in which high energy steam/water lines were routed from the drain headers of all major heat exchangers into the combustion space. When allo wed flow, these lines were used to emulate tube leaks from any of the major heat exchangers. Their flow rates and locations were then compared to Tube Failure Model predications. This testing is considered significant as for the first time Äheat rate effects of tube failures will be directly determined; and, further, this testing will provide the Tube Failure Model its on-line proof-of-process.

The paper investigates the effect of adding a second 1072 MVA turbogenerator to an existing one in a power station feeding a series capacitor compensated transmission line. In carrying out the investigation, the new two-generator system is modelled as one equivalent generator with increased capacity, and also as a multimachine system with two separate generators. A comparison of these models shows that, for this type of stability study and this transmission system configuration, there is no advantage gained in modelling the two generators separately rather than as one equivalent generator. The results further show that conditions can exist where the system is stable with one generator but unstable with two, and vice versa.

The techno-economic parameters that influence the commercial deployment of hybrid thermophotovoltaic (TPV) solar power generation are determined using annual system simulations. It has been found that a TPV cell price of E5/cm 2 or less together with a TPV operating temperature under 800°C is required for a hybrid solar-biomass TPV power plant to be economically competitive with the state-of-the-art hybrid solar-biomass Rankine cycle power plants. 162 Hussain CMI, Duffy A and Norton B (2019) Economic appraisal of hybrid solar-biomass thermophotovoltaic power generation.

Single-shaft gas turbine and its cycles are sensitive to frequency drops and, therefore, sudden change loads or large frequency dips might affect their stability. This phenomenon is related to the reduction of the air mass flow passing through the machine during the frequency dips, which might lead to an interaction between governor and temperature control loop. In this paper, the performance of the combined cycle and steam-injected gas turbine are studied during frequency dips and transient maneuvers. For this purpose, two similar units are developed based on these cycles and their performances are studied in different scenarios. The simulation results show that the steam injected gas turbine has a better performance during frequency drops and it can handle relatively larger change loads.

LEFM CheckPlus chordal ultrasonic flowmeters typically provide nuclear and fossil feedwater mass flow measurements with uncertainties of about ± 0.3% at a 95% confidence level. The largest contributor to this uncertainty is the uncertainty in meter factor—typically in the ± 0.2 to ± 0.25% range. The meter factor and its uncertainty are established, for each CheckPlus system, by a series of calibration tests in a certified hydraulic facility. The test series is extensive. The hydraulic configuration of the intended plant installation is modeled in full scale, then varied parametrically, thereby establishing a “base” meter factor and characterizing variations in that meter factor with variations in hydraulic geometry. The parametric tests also provide a basis for extrapolating calibration results to plant conditions. This process utilizes quantitative measures of the velocity profile made during the calibration tests and in the plant to ensure that the pertinent characteristics of the...

Nowadays the refining sector in Mexico needs to increase the quantity and quality of produced fuels by installing new process plants for gasoline and ultra low sulphur diesel. These plants require the provision of electricity and steam, among other services to function properly, which can be supplied by the power plants currently installed in each refinery through an expansion of their generation capacity. These power plants need to increase its production of electricity and steam at levels above their installed capacity, which involves the addition of new power generating equipment (gas or steam turbo-generators) as well as the raise of the electrical loads. Currently, the Mexican Petroleum Company (PEMEX) is planning to restructure their electrical and steam systems in order to optimally supply the required services for the production of high quality fuels. In this paper the present status of the original electrical power systems of the refineries is assessed and the electrical in...

Reliability is one of the essential factors that affects the performance of power stations. The current study deals with step down station transformers that transform electricity from 33000 KV to 11000 KV. The process of the fitting model requires data collection and analysis for use in estimating the parameters required to ascertain the suitable probability distributions. In the present paper, we determined the distribution fitting to time between failure (TBF). The model data were collected from ten stations from an electricity distribution company in Iraq. This paper describes the distribution fitting for one station based on failure data collection, calculated TBF, plotted the histogram for TBF, and matched the plot on the continuous distributions' functions. After conducting data analysis, the most valid distribution was found to be the Exponential distribution.

Single-shaft gas turbine and its cycles are sensitive to frequency drops and, therefore, sudden change loads or large frequency dips might affect their stability. This phenomenon is related to the reduction of the air mass flow passing through the machine during the frequency dips, which might lead to an interaction between governor and temperature control loop. In this paper, the performance of the combined cycle and steam-injected gas turbine are studied during frequency dips and transient maneuvers. For this purpose, two similar units are developed based on these cycles and their performances are studied in different scenarios. The simulation results show that the steam injected gas turbine has a better performance during frequency drops and it can handle relatively larger change loads.

Comprehensive emission inventories for 2001 and 2004 for Kuwait's main power stations located at Al-Doha and Al-Subyia have been prepared. These inventories are inserted, in conjunction with meteorological data, into the Source Complex model for Short Term Dispersion (ISCST4.5) to predict ambient ground level concentrations of sulphur dioxide (SO 2) and nitrogen oxides (NOx) at selected receptors for years 2001 and 2004. The comparison of the results obtained for these two years show the influence of increase in emission rates due to urban and industrial growth. For model validation, computed results are compared with the measured daily average values of SO 2 and NOx collected at a fixed Kuwait Environment Protection Agency air quality monitoring station located at the roof of polyclinic in Rabia. Individual contributions of each power station to the highest predicted values are assessed. The five highest hourly, daily and annual ground level concentration values under prevailing meteorological conditions are compared for 2001 and 2004. It is found that the hourly mean concentrations are strongly influenced by the prevailing meteorological conditions. The effect of meteorological conditions has not been that dominant for the daily and annual mean values and the predicted values for 2004 are higher than 2001, simply corresponding to a high emission rates, especially in summer months. Top fifty daily average values show a slope of 0.806 for 2001 which means that the model predictions are 20% less than the observed levels. However, the predicted slope for 2004 is 0.96 and the model predictions are in very close agreement with the observed data.

Reliability is one of the essential factors that affects the performance of power stations. The current study deals with step down station transformers that transform electricity from 33000 KV to 11000 KV. The process of the fitting model requires data collection and analysis for use in estimating the parameters required to ascertain the suitable probability distributions. In the present paper, we determined the distribution fitting to time between failure (TBF). The model data were collected from ten stations from an electricity distribution company in Iraq. This paper describes the distribution fitting for one station based on failure data collection, calculated TBF, plotted the histogram for TBF, and matched the plot on the continuous distributions' functions. After conducting data analysis, the most valid distribution was found to be the Exponential distribution.

Biogas Technology in Ghana is relatively underdeveloped and has been limited to donor-funded projects in communal areas and health institutions. In most cases the projects have been abandoned for lack of sustained funding, poor maintenance and management. Where there is any technical utilization of the technology, these have been limited to the production of Biogas for heating water and for cooking purposes with little or poor maintenance of the equipment used.. A survey carried out by the authors indicated that in almost all cases there is an under-utilisation of the gas produced. The Ministry of Energy, whilst recognising the growing importance of renewable energy in meeting the policy objectives of securing future energy for strategic applications in addition to minimising the environmental impacts of energy supply, particularly in a country that has no known appreciable reserves of oil, it has not come out with a clear policy statement for the research, development and promotion of biogas technology. The present study focuses on the development of biogas technology for industrial application in the Kumasi Abattoir, through the use of the animal waste produced for the production of Biogas, namely for heat and electricity generation with the resultant effect of creating an economically viable and thereby sustained venture for the private sector..

En el trabajo se valida el procedimiento vigente de actualización de la característica energética (curvas consumo-entrega) de los bloques, evidenciándose la no correspondencia de los modelos obtenidos con el comportamiento real. Se proponen tres vías posibles de obtención de la información para un nuevo método de actualización a partir de la instrumentación existente que incluye el empleo de la información de los sistemas SCADA instalados. Palabras clave: Centrales termoeléctricas, turbina de vapor, curva de arranque, rodaje, preparación para la sincronización This paper deals with the validation of the now in use, updating procedure of fuel rate curves (energy characteristic) of units, it shows no correspondence with the actual (situation) behavior. Three possible ways to obtain the information to update models are proposed based on the monitoring installed equipment data which include the use of information of installed SCADA systems.

Nowadays the refining sector in Mexico needs to increase the quantity and quality of produced fuels by installing new process plants for gasoline and ultra low sulphur diesel. These plants require the provision of electricity and steam, among other services to function properly, which can be supplied by the power plants currently installed in each refinery through an expansion of their generation capacity. These power plants need to increase its production of electricity and steam at levels above their installed capacity, which involves the addition of new power generating equipment (gas or steam turbo-generators) as well as the raise of the electrical loads. Currently, the Mexican Petroleum Company (PEMEX) is planning to restructure their electrical and steam systems in order to optimally supply the required services for the production of high quality fuels. In this paper the present status of the original electrical power systems of the refineries is assessed and the electrical in...

Instant coffee is produced worldwide by spray drying coffee extract on an industrial scale. This production process is energy intensive, 70% of the operational costs are due to energy requirements. This study aims to identify the potential for energy and cost improvements by performing a conventional and advanced exergy and exergoeconomic analysis to an industrial-scale spray drying process for the production of instant coffee, using actual operational data. The study analyzed the steam generation unit, the air and coffee extract preheater, the drying section, and the final post treatment process. The performance parameters such as exergetic efficiency, exergoeconomic factor, and avoidable investment cost rate for each individual component were determined. The overall energy and exergy efficiencies of the spray drying system are 67.6% and 30.6%, respectively. The highest rate of exergy destruction is located in the boiler, which amounts to 543 kW. However, the advanced exergoeconomic analysis shows that the highest exergy destruction cost rates are located in the spray dryer and the air heat exchanger (106.9 $/h and 60.5 $/h, respectively), of which 47.7% and 3.8%, respectively, are avoidable. Accordingly, any process improvement should focus on the exergoeconomic optimization of the spray dryer.

This narrative review paper begins with a brief history of biogas digesters in South Africa followed by a listing of the biogas digesters that have been installed in the country then the critical analyses of the different types of small scale biogas digesters since the introduction of the biogas technology into the country in the year 1957. The analysis is done on a basis of conducted studies and observations of the strengths and limitations of each small scale digester design installed. It is the aim of the review to help stakeholders in the selection of the most appropriate digester type well suited to their environmental conditions and to fill the knowledge gap existing in the biogas technology and hence making it easier to map of a way forward into the design of improved anaerobic digesters. In this review, the in-situ cast concrete digester has been analyzed to be the most suitable design for installation in the South African context though stakeholders can still do their own selection based on the analyses of the other designs. Some recommendations of aspects to consider in the introduction of a new design are also given.

Accurate average flow velocity determination is essential for flow measurement in many industries, including automotive, chemical, and oil and gas. The ultrasonic transit-time method is common for average flow velocity measurement, but current limitations restrict measurement accuracy, including fluid dynamic effects from unavoidable phenomena such as turbulence, swirls or vortices, and systematic flow meter errors in calibration or configuration. A new spatial averaging method is proposed, based on flexural ultrasonic array transducer technology, to improve measurement accuracy and reduce the uncertainty of the measurement results. A novel two-dimensional flexural ultrasonic array transducer is developed to validate this measurement method, comprising eight individual elements, each forming distinct paths to a single ultrasonic transducer. These paths are distributed in two chordal planes, symmetric and adjacent to a diametral plane. It is demonstrated that the root-mean-square dev...

Accident risks are compared across a broad range of energy technologies. Analysis of historical experience was based on the comprehensive database ENSAD. OECD and EU 27 performed significantly better than non-OECD countries. External costs of accidents are very small, but impacts can still be enormous. No technology performs best for all risk indicators; thus tradeoffs are inevitable.

The electrification of the transportation sector is seen as a main pathway to reduce CO2 emissions and mitigate the earth's climate change. Currently, Electric Vehicles (EVs) are entering the market fast. Although EVs have not been used as ambulances yet, the transition to the new type of vehicle is a matter of time. Thus, in this paper we discuss a number of research questions related to the efficient deployment of electric ambulances, focusing on the Artificial Intelligence (AI) point of view and we propose a framework for developing online algorithms that schedule the charging of electric ambulances and their assignment to patients.

An inherent characteristic of all gas turbines (GT) is their inability to maintain constant power output as ambient temperature increases or at high elevation. Consequently, electrical generation and horsepower output are in greatest demand at high ambient temperatures. On a 35°C (95°F) day, a GT’s air mass flow-rate is reduced by up to 10% and power reduced by 15% compared to its ISO performance. Dry air injection (DAI) provides constant replacement of air mass flow-rate, injected into the gas turbine’s compressor plenum over a wide range of ambient temperatures and altitudes allowing the GT to maintain ISO-like or better conditions irrespective of temperature or elevation. The ability to generate additional, cost-effective, fast & reliable power solutions in challenging conditions, enable industrial gas turbine (IGT) owners to realize a distinct competitive advantage, generate a return on their investments and drive stakeholder value. Dry air injection stands out as the world’s fi...

Lucrarea prezintă o abordare complet nouă şi originală a analizei ireversibilitatilor generate în timpul funcţionării maşinilor frigorifice cvasi-Carnot cu vapori. În acest articol sunt dezvoltate expresii pentru calculul sursei interne de generare a entropiei şi a coeficientului de performanţă, în funcţie de viteza finită a procesului şi de alţi parametri, precum temperatura vaporilor, raportul de comprimare/destindere, debitul masic şi proprietăţile vaporilor pentru fiecare proces ce se desfaşoară cu viteză finită în maşinile frigorifice ireversibile cvasi-Carnot. În cadrul acestor calcule sunt luate în considerare proprietăţile gazului real. Această abordare, bazată pe Metoda Directă, propune o alternativă viabilă pentru proiectarea şi optimizarea acestui tip de maşini. The paper presents a completely new and original approach of quasi-Carnot refrigeration machines working with vapor. It provides expressions for calculating the internal entropy generation source and COP, as a function of the finite speed of the process and other parameters such as temperature of the vapor, compression/expansion ratio, mass flow rate and vapor properties for each finite speed process of the reversed irreversible quasi-Carnot cycle refrigeration machines. The real gas properties are considered in these calculations. This approach, based on the Direct Method, becomes an important issue in design and optimization of such machines.

This paper describes a real-time performance monitoring method based on PTC 4-2013 for determining instantaneous heat rates for coal-fired power plants. The calculation protocol uses a modified output–loss approach applied to a control volume that closely conforms to the boiler. The largest energy balance term is the heat transfer rate to the steam, which is known accurately in real-time when the plant employs properly calibrated instrumentation. The first-law energy balance also requires a balanced combustion equation which depends on coal composition, which is not known in real-time. A periodic or alert-driven calibration utilizes an ultimate analysis of a carefully collected coal sample and historic plant data obtained during the collection time of the coal sample. This is used to calculate correction factors for the coal mass flowrate, air preheater leakage, and CO2 and SO2 concentrations at the economizer exit derived from continuous emissions monitoring systems (CEMS) measurem...

This paper presents the thermodynamic and cost analysis of a coal-based zero-atmospheric emissions electric power plant. The approach involves an oxygen-blown coal gasification unit. The resulting synthetic gas (syngas) is combusted with oxygen in a gas generator to produce the working fluid for the turbines. The combustion produces a gas mixture composed almost entirely of steam and carbon dioxide. These gases drive multiple turbines to produce electricity. The turbine discharge gases pass to a condenser where water is captured. A stream of carbon dioxide then results that can be used for enhanced oil recovery or for sequestration. The term zero emission steam technology is used to describe this technology. We present the analysis of a 400MW electric power plant. The power plant has a net thermal efficiency of 39%. This efficiency is based on the lower heating value of the coal, and includes the energy necessary for coal gasification, air separation, and for carbon dioxide separati...

h i g h l i g h t s An exergetic analysis is used to identify the thermodynamic irreversibilities of a power plant. The plant includes a solid-oxide fuel-cell unit and CO 2 capture. Additional power generated in the fuel-cell unit enhances the power output of the plant. The power plant results in a high efficiency compared both to conventional and other CO 2 capture plants. High irreversibilities are found for the solid-oxide fuel cell.

The accurate measurement of flow rate is an important and an integral part of sustainable water management. The errors associated with measurements are directly dependent on the quality of measurements. The aim of this study was to verify this accuracy and analyse the testing methodologies used to facilitate subsequent verification and to assess the accuracy, suitability and cost-effectiveness of in situ verification techniques and technologies for closed conduits. The following techniques were reviewed: meter installations gravimetric method, ultrasonic clamp-on method, insertion meters, electromagnetic meters, tracer methods, reference meters in series, and electronic verification of electromagnetic flow meters. All techniques were evaluated from the perspective of the Australian National Measurement Institute (NMI) requirements for accuracy. A survey and an industry consultation were also conducted across Australia. Two key insights were: (i) in situ verification is an area that few water authorities have had any experience with, and (ii) the lack of available information regarding the economic viability and water accounting benefits of in situ verification. Generally, there is confusion or not enough information about the costs/benefits of in situ verification, or about proven techniques for in situ verification and how to deal with installation and site issues.

The accurate measurement of flow rate is an important and an integral part of sustainable water management. The errors associated with measurements are directly dependent on the quality of measurements. The aim of this study was to verify this accuracy and analyse the testing methodologies used to facilitate subsequent verification and to assess the accuracy, suitability and cost-effectiveness of in situ verification techniques and technologies for closed conduits. The following techniques were reviewed: meter installations gravimetric method, ultrasonic clamp-on method, insertion meters, electromagnetic meters, tracer methods, reference meters in series, and electronic verification of electromagnetic flow meters. All techniques were evaluated from the perspective of the Australian National Measurement Institute (NMI) requirements for accuracy. A survey and an industry consultation were also conducted across Australia. Two key insights were: (i) in situ verification is an area that few water authorities have had any experience with, and (ii) the lack of available information regarding the economic viability and water accounting benefits of in situ verification. Generally, there is confusion or not enough information about the costs/benefits of in situ verification, or about proven techniques for in situ verification and how to deal with installation and site issues.

PROSPECT OF ADVANCED GENERATION TECHNOLOGIES IN A COMPETITIVE MARKETPLACE To meet the challenge of deregulation and customer demands for a free competitive market, the electric utility industry in the U.S. (and, for that matter, throughout the world) will experience tremendous changes over the noa five years. These changes will be driven by two major forces: the deregulation of the industry and, therefor; no guaranteed return on investment but more importantly, the demands of customers for a free competitive market in the electric utility industry where they can achieve the lowest cost for the commodity. This will force utility companies to position themselves as low-cog producers. Although low cost does not necessarily mean success, it is obvious that cutting and/or reducing capital expenditures will play the most important role. Unregulated markets encourage product diversity, as firms look for 'niche* profit opportunities. A pervasive lesson from other industries that have recently been deregulated clearly shows that unless properly planned, these companies will not only do poorly but may be completely wiped out from the market Generation Planning (base load vs. peak load, long-terrn vs. short-term) will become more important since two-thirds of the capital investment is tied to generation facilities. While low-cost utilities will have greater flexibility in adapting to competition, they will be far from immune to industry changes. Under a fully competitive marketplace, all generating plant assets/investments will come out of a rate base. Since all companies will be exposed to competition, high-cost generating assets would no longer be subsidized by ratepayers. This will force the utility companies to invest in low capital cost generation only, at least during the next ten to fifteen years. This paper will briefly discuss the status of various advanced generation technologies with respect to their costs, applicability and limitations, where these technologies are expected to be cost effective and finally how these technologies compare with the state-of-the-art combined cycle gas-turbine technology. It is predicted that as environmental regulations tighten on pollution, advanced generation technologies may benefit at the expense of current fossil fuel technologies. However, it is not certain whether economic growth in the U.S. can be sustained if new regulations on pollution force to add new plants with advanced generation technologies, compared to continuing with today's generation mix. It will be examined how, when and where the advanced generation technologies would play an important role in penetrating the market on their own merits.

This paper presents the thermodynamic analysis of a coal-based zero-atmospheric emissions electric power plant. The approach involves an oxygen-blown coal gasification unit. The resulting synthetic gas (syngas) is combusted with oxygen in a gas generator to produce the working fluid for the turbines. The combustion produces a gas mixture composed almost entirely of steam and carbon dioxide. These gases drive multiple turbines to produce electricity. The turbine discharge gases pass to a condenser where water is captured. A stream of carbon dioxide then results that can be used for enhanced oil recovery, or for sequestration. This analysis is based on a 400 MW electric power generating plant that uses turbines that are currently under development by a U.S. turbine manufacturer. The power plant has a net thermal efficiency of 42.6 %. This efficiency is based on the lower heating value of the coal, and includes the energy necessary for coal gasification, air separation and for carbon dioxide separation and sequestration. The paper also presents an analysis of the cost of electricity (COE) and the cost of conditioning carbon dioxide for sequestration for the 400 MW power plant. Electricity cost is compared for three different gasification processes (Texaco, Shell, and Koppers-Totzek) and two types of coals (Illinois #6 and Wyodak). Cost of electricity ranges from 5.16 ¢/kWhr to 5.42 ¢/kWhr, indicating that the cost of electricity varies by 5% for the three gasification processes considered and the two coal types used.

The paper presents a new type of Renewable Energy Sources (RES) suitable for exploitation watercourse with periodical-temporary water flow. This innovative solution consist of Hydroelectric Plant (HEP) and solar Photovoltaic (PV) generator working together as one hybrid power plant, producing green energy with the same characteristics as classical hydroelectric plants. The main objective of this hybrid solution is achievement of optimal renewable energy production in order to increase the share of RES in an Electricity Power System (EPS). As a paradigm of such exploitation of RES, the example of HEP Zavrelje/ Dubrovnik in Croatia was used, where it was ascertained that the proposed solution of hybrid PV-HEP system is natural, realistic and very acceptable, which enhances the characteristics of both energy sources. The application of such hybrid systems would increase the share of high quality RES in energy systems.

Rural Ghana has potential for widespread use of biogas energy by households, which would contribute to the achievement of UN's Sustainable Development Goal 7 (affordable and clean energy). However, knowledge of households' willingness to adopt it is still scanty. Therefore, this paper examines socioeconomic factors that may influence the willingness of households in the Birim North District of Ghana to adopt biogas energy for cooking. Using survey data, the study analyses the effects of gender, age, education and occupation of household heads, household size, type of energy currently used for cooking, household expenditure on energy for cooking, income and prior awareness on willingness to adopt biogas. Data were collected from a random sample of 392 households, and analysed using chi-square and multiple binary logistic regression methods. With the exception of education, all the socioeconomic variables stated above have significant effects on households' willingness to adopt biogas technology. However, the exact nature of the influence of these variables (i.e. whether negative or positive) does not necessarily conform to what pertains elsewhere. The findings provide local governments and other stakeholders with relevant insights to properly target households with appropriate educational and marketing strategies for biogas adoption.

Sodium hypochlorite (NaOCl) is widely used to disinfect seawater in power plant cooling systems in order to reduce biofouling, and in ballast water treatment systems to prevent transport of exotic marine species. While the toxicity of NaOCl is expected to increase by ongoing ocean acidification, and many experimental studies have shown how algal calcification, photosynthesis and growth respond to ocean acidification, no studies have investigated the relationship between NaOCl toxicity and increased CO 2. Therefore, we investigated whether the impacts of NaOCl on survival, chlorophyll a (Chl-a), and effective quantum yield in three marine phytoplankton belonging to different taxonomic classes are increased under high CO 2 levels. Our results show that all biological parameters of the three species decreased under increasing NaOCl concentration, but increasing CO 2 concentration alone (from 450 to 715 μatm) had no effect on any of these parameters in the organisms. However, due to the synergistic effects between NaOCl and CO 2 , the survival and Chl-a content in two of the species, Thalassiosira eccentrica and Heterosigma akashiwo, were significantly reduced under high CO 2 when NaOCl was also elevated. The results show that combined exposure to high CO 2 and NaOCl results in increasing toxicity of NaOCl in some marine phytoplankton. Consequently, greater caution with use of NaOCl will be required, as its use is widespread in coastal waters.

Renewable energy sources with their growing importance represent the key element in the whole transformation process worldwide as well as in the national/global restructuring of the energy system. It is important for a sufficient energy system is to find a solution and key element to complete energy supply, that is, energy storage. Reasons and background, which make the energy storage so crucial, imply that exact, enduring development of energy storage is an indispensable part of the full energy supply. There are some necessary components for further development and implementation of renewable energy sources, and these components involve not only a flexible generation system but also network expansion, demand-side integration, and storage. As the energy storage is a much needed component that can facilitate a low carbon energy system, energy storage technologies find their applications in two major areas, and these are electricity network energy storage and transport/mobility. Interest toward energy storage has also grown due to technical and innovative progress in the field of energy storage technologies. Additionally, energy storage can be considered from different perspectives, which always give corresponding benefits, emphasizing the importance and attractiveness of energy storage.

Results of investigating the additional error of ultrasonic flowmeters caused by the distortion of the flow are presented in the article. The location coordinates of acoustic paths were calculated for their number from 1 to 6 according to the different numerical integrating methods: Gauss (Gauss-Legendre, Gauss-Jacobi), Chebyshev (equidistant location of acoustic paths), Westinghouse method, method of OWICS (Optimal Weighted Integration for Circular Sections). This made it possible to realize the flowrate equation for multi-path ultrasonic flowmeters and to determine their additional error for different location of the acoustic paths. The average flow velocity along each path is calculated based on the flow velocity profile in the pipe cross section. Four two-peak Salami functions of velocity are used to calculate the velocity profile of the distorted flow caused by typical local resistances. According to the research results the recommendations were developed for choosing the number of the acoustic paths of the ultrasonic flowmeters and for using the methods for determining the location coordinates of the acoustic paths.

Exergy-based methods are powerful tools for developing, evaluating, understanding, and improving energy conversion systems. This paper deals with integrated advanced exergybased evaluations. In addition to conventional methods, advanced exergy-based analyses consider (a) the interactions among components of the overall system, and (b) the real potential for improving each important system component. The main role of an advanced analysis is to provide energy conversion system designers and operators with information useful for improving the design and operation of such systems. Splitting the exergy destruction, the capital investment cost, and the component-related environmental impact associated with each single component of an energy conversion system into endogenous/exogenous and avoidable/unavoidable parts and using a further splitting of the exogenous exergy destruction improves (a) our understanding of the processes that take place,

This paper examines the sensitivities of ambient conditions on the most basic understanding of fossil-fired power plants: boiler efficiency and associated computed fuel flow. Conditions studied were ambient oxygen in the combustion air, and the air’s water content. This research was conducted at the 610 MWe Boardman Coal Plant operated by Portland General Electric. Burning Powder River Basin coal, it has been tested numerous times by the authors including several 4 to 6 month long projects used to throughly understand the system. This experience, coupled with many other such projects, has suggested that ambient oxygen and humidity - normally  taken as constants or simply ignored in common analyses - may have significant influence on boiler efficiency.
There are, of course, any number of inputs which might affect a computed efficiency, and associated computed fuel flow. This work separates data making up  efficiency into water-side data and system stoichiometric data. We argue that fundamental understanding of fossil-fired systems begins with system stoichiometrics, and, for this work, ambient oxygen and humidity. 
Demonstrated is that depletion of ambient oxygen can cause a very high error in boiler efficiency (>1% Δη) if unrecognized. In addition, given intrinsic complexity of combustion air systems, uncertainty in the amount of water in combustion air can well contribute to error. Further, this work demonstrates a technique whereby plant fuel flow can be verified based on ambient conditions.
This paper demonstrates the very real advantage of using high accuracy ambient instrumentation - for oxygen and relative humidity - whose measurements may not have dramatic affects when used at a well run plant such as Boardman, but whose use at plants not well monitored will easily justify their employment. Taking such ambient measurements a step further, this paper demonstrates a method whereby ambient humidity can be used to verify a coal-fired plant’s fuel flow.

This paper presents a conceptual model of a 200-kWe Solid Oxide Fuel Cell – Gas Turbine (SOFC-GT) plant operating on biomass derived synthetic gas. The plant also has a Heat Recovery Steam Generator (HRSG) integrated at the GT exhaust, producing low-pressure process steam. The SOFC has been considered to be of tubular cell construction and internally reforming type. The reaction kinetics of the reforming and shifting reactions have been integrated with the cell electrochemical model. Simulated thermodynamic performance of the modeled plant in terms of electrical power, efficiency and process heat is presented and analyzed. Influences of variations in operating pressure and gas composition, on the plant performance are also reported.

1) Rostock University, Faculty of Mechanical Engineering and Marine Technology, Chair of Environmental Technologies, Justus-von-Liebig-Weg 6, D - 18059 Rostock, Germany Tel.: +49 (0) 381-498-9433/31 2) Hanoi University of Agriculture-Hanoi/Vietnam, Faculty of ...

En este trabajo de investigación se evaluó la factibilidad de usar series sintéticas de caudales medios mensuales para la determinación de los costos marginales promedio de energía del Sistema Eléctrico Interconectado Nacional del Perú – SEIN, tomándose como caso de aplicación el estudio de la Fijación de Tarifas en Barra del año 2004, donde se usó el modelo de simulación, planificación y optimización del sistema energético y eléctrico peruano llamado modelo PERSEO. El modelo es usado actualmente por la Gerencia Adjunta de Regulación Tarifaría (GART) del Organismo de Supervisión de la Inversión en Energía y Minería – OSINERGMIN. El modelo usa como información hidrológica series de caudales medios mensuales de afluentes en los puntos de interés de las 23 cuencas hidrográficas del SEIN, siendo una de las principales la cuenca del lago Junín, cuyo recurso hídrico es usado por las centrales hidroeléctricas Mantaro y Restitución, generando casi el 20% de la energía eléctrica de nuestro p...

Most renewable energy sources depend on climatic circumstances and lack consistency even during a single day. The Hybrid System (HS) solves this drawback by relying on many types of renewable sources and managing them to get a satisfactory continuous power. In this paper, a grid connected HS composed of a Proton Exchange Membrane Fuel Cell (PEMFC), a Photovoltaic panel (PV), a battery and a Supercapacitor (SC) is proposed. Sources are pushed to deliver their maximum power thanks to a Maximum Power Point Tracker (MPPT). The output voltage of each component is regulated using a buck converter controlled by a type-III compensator. Consequently, HS components share the power on a single DC bus. The proposed topology offers a simple management technique using an affordable system controller. In order to illustrate our approach, a prototype is modeled, simulated and implemented on an emulator of a real system.

Nowadays the refining sector in Mexico needs to increase the quantity and quality of produced fuels by installing new process plants for gasoline and ultra low sulphur diesel. These plants require the provision of electricity and steam, among other services to function properly, which can be supplied by the power plants currently installed in each refinery through an expansion of their generation capacity. These power plants need to increase its production of electricity and steam at levels above their installed capacity, which involves the addition of new power generating equipment (gas or steam turbo-generators) as well as the raise of the electrical loads. Currently, the Mexican Petroleum Company (PEMEX) is planning to restructure their electrical and steam systems in order to optimally supply the required services for the production of high quality fuels. In this paper the present status of the original electrical power systems of the refineries is assessed and the electrical in...

The combination of hydroelectric and photovoltaic sources of energy in a generation system may seem unfeasible due to the still quite high costs of the photovoltaic plants. However in the next few decades, significant reductions in those costs are to be expected. Moreover, this combination may reduce the cost of plants implemented in low hydroelectric potential sites for which main system interconnection costs prove prohibitive. The study of hybrid hydro-PV generating plants allows the evaluation of the use of water reservoirs and battery banks as alternatives for energy storage within a system. It also allows the evaluation of the advantages of generation from complementary energy sources. The objectives of this paper is to propose the concept of a theoretical performance limit for the plants and propose a method for the determination of this performance limit using computer simulations with idealized energy availability functions. Using this method, the effect of different degrees of complementarity in time of the energy resources on the performance of hydro PV plants is studied. It has been observed that, as expected, the smallest failure indexes measuring the energy supply to the consumers are associated to the best complementarity in time indexes. The results of the simulations led to the synthesis of failure index curves, as functions of the different degrees of complementarity in time, with data obtained solely with the utilization of idealized functions describing the energy availabilities, as proposed in this work. The results so obtained are a preliminary set treating the influence of the complementarity characteristics on the performance of hybrid plants based on hydro and solar energies and show how the complementarity characteristics may be used to design hybrid power generation systems showing improved efficiency. The subsequent research work shall proceed to at least two different phases. In the first one, the method exposed in the present work shall be applied to real data and compared to the operation of existing hydro PV plants. In the second phase the obtained relations of the performance of the system to the different degrees of complementarity shall be confronted with design parameters of hydroelectric-photovoltaic plants based on complementary resources.

The power generation from biomass requires the water to clean the producer gas for use in engines. The water used as cleaning agent gets contaminated with organic and inorganic compound and becomes highly polluted. The study was conducted to develop low cost water treatment plant to enhance water use efficiency by increasing the recycling duration. The charcoal received from gasifier was thermally treated for its activation and used to treat the waste water. The study reviled that 0.5 to 1.0 cm charcoal with 35 cm bed height was found effective for reduction in turbidity and COD present in the effluent water of biomass based power plant.